The present invention relates to non-destructive direct measurement for detection and quantification of surface and bulk corrosion and erosion real-time in metals, non-metallic materials (such as plastics, polymers, cement, concrete, ceramics, rocks and soils) and composites in the field and laboratory.
Surface and bulk corrosion and erosion of metals and non-metallic materials is one of the oldest problems that has ever challenged the industrial world. The estimated losses due to these corrosion and erosion problems are in the billions of dollars per year in the U.S. alone. Surface and bulk corrosion and erosion are the gradual physiochemical-thermo-mechanical destruction of materials by the action of the environment and/or applied loading conditions. Corrosion or erosion of the material will result in degrading many other material properties. At present there is no real-time technology available to rapidly detect and quantify surface and bulk corrosion and erosion in a non-destructive way in situ from very small to very large areas of the material in the laboratory to the field.
One of the main needs that arises in the gas and oil industry during drilling and distributions of crucial energy sources is maintaining the longevity and reliability of drilling tools, casing connections and distribution pipelines. Also, in the civil infrastructures including foundations, piles, pipelines, buried structures, bridges, highways and buildings, there is urgent need for detecting the surface and bulk corrosion and erosion related deterioration of various structural and non-structural components for maintenance and extending the service life. Such objective is compromised mostly because of the presence of corrosion and erosion, both surface and bulk, which cannot be easily detected and quantified. Corrosion and erosion are naturally occurring phenomena commonly defined as the deterioration of a substance (usually a metal) or its properties because of a reaction with its environment. For the past two decades, there has been a tremendous amount of research focused on smart coatings for structural applications, such as coatings that can sense certain conditions and then respond. These are coatings that typically contain one or more indicators that can sense conditions such as corrosion and respond by means of changes in pH, color, fluorescence or a combination thereof (Harovel G. Wheat, 2012). In the industry of gas and oil, corrosion and erosion of steel casing in cement mortar, insulated pipelines and reinforced concrete is of concern because it requires almost immediate repairs and rehabilitation to extend the service life of the structures. Similarly in the area of civil infrastructures, surface and bulk corrosion and erosion in buried structures and above ground structures must be detected for rehabilitation to extend the service life of the facilities.
Some research has investigated using electrical resistance as a measure of corrosion and erosion protection provided by coatings. This research focused on the interaction of the metal-coating system with corrosive fluid environments such as NaCl solution and H2504 solution. The studies mainly focused on the change in the coating that arises from presence of corrosion and erosion products. Those studies did not address the changes in interface electrical properties. Other research studies have been focused on coatings that typically contain one or more indicators that can sense condition such as corrosion and respond by means of changes in pH, color, fluorescence or a combination thereof (Harovel G. Wheat, 2012). The applicability of such coatings for the steel casing in oil wellbores is difficult and impractical to monitor due to the changes that the coatings may exhibit as a result of the inaccessible nature of wellbore.